The present invention relates to a dispatching method of manufacturing integrated circuit (IC), and more particularly, to a dispatching method by push and pull two-way in accordance with the needs of each workstation.
As the semiconductor processes develop to use very large scale integration (VLSI) technology, all the IC processes become more complex and difficult. Hundreds of steps are needed to manufacture IC chips with high integration, and a lot of wafers are manufactured by using numerous different workstations that may reuse the apparatuses of the same type, and lots of wafers are manufactured by using the workstation with the same type of apparatuses. Thus, the complexity of dispatching is increased for such inextricable processes. For the semiconductor industries, due to the limited resources of the IC factory, it is the most important to map out the optimal dispatching principles so as to form the production line with high efficiency. Unsuitable dispatching principles frequently delay the process cycle time, and even reduce the utility of the apparatuses, and hence the custom satisfaction is reduced due to decrease of the flexible cycle life of products. With regarding to topic discussed above, semiconductor industries usually can increase outputs and achievements of apparatuses by improving dispatching principles, and cut down the waiting time of lots of wafers in production lines simultaneously, wherein properly determining the priorities of lots of wafers can decrease the cycle time of processes, and increase utilities of equipments, and deliver the goods on time.
FIG. 1 illustrates the general dispatching method of manufacturing IC. Referring to FIG. 1, in IC factories, after obtaining the data of work in processes (WIP) 10 in equipments, priorities of lots of wafers are determined by respective parameters and method 12, such as the delivery time and production of equipments, etc., and lots of wafers are dispatched by each of the priorities 14, and then the dispatching procedures of equipments are finished accordingly.
In consideration of increasing outputs and achievements of apparatuses, and cutting down the waiting time of lots of wafers in production lines, the aspect of the present invention is to provide a preferred dispatching method of lots of wafers.
Referring to the aforementioned aspect, when lots of wafers with priorities is manufactured in processes by a plurality of apparatuses, the two-way dispatching method of the present invention decides the orders of lots of wafers manufactured in processes, wherein the processes are composed of a plurality of stages, and the stages are composed of a plurality of workstations. The two-way dispatching method of manufacturing IC of the present invention includes: performing a first push step to dispatch first lots of wafers with a compulsory order to each workstation; calculating capacity of each of the equipments, and then gathering a plurality of first deficiencies of equipments; performing a first pull step, if an amount of lots of wafers is less than a full load manufactured in a first stage and has a first vacancy, then dispatching a second lots of wafers into a second stage in front of the first stage, wherein the second lots of wafers have same amount as the first vacancy; calculating capacity of each of the equipments, and then gathering a plurality of second deficiencies of equipments; performing a second pull step, if an amount of lots of wafers is less than a full load manufactured in a first workstation with a second vacancy, then dispatching a third lots of wafers into a second workstation in front of the first workstation wherein the third lots of wafers have same amount as the second vacancy, and the first and the second workstation are in the same stage; calculating capacity of each of the equipments, and then gathering a plurality of third deficiencies of equipments; performing a second push step, dispatching lots of wafers by the priority into the workstations which do not have the full load.
In the two-way dispatching method of manufacturing IC of the present invention, the lots of wafer with a compulsory order include lots of wafers with a special priority, delayed lots of wafers and idle lots of wafers so as to influence the processes of manufacturing IC. In addition, the second is next to the first stage, and the second workstation is next to the first workstation.
When the first stage is the last one of the stages, the two-way dispatching method of manufacturing IC of the present invention even includes repeating the first pull step to dispatch from the second stage to the first one of the stages in turn, thereby dispatching all stages are dispatched. Similarly, when the first workstation is the last one of the workstations, the two-way dispatching method of manufacturing IC of the present invention even include repeating the second pull step, to dispatch from the second workstation to the first one of the workstations in turn, thereby dispatching all workstations in the same stage.
Applying to dispatching method of wafers, the two-way dispatching method of manufacturing IC of the present invention even include: providing a database which has process data of lots of wafers manufactured in each of the workstations; determining priorities of lots of wafers by the process data; obtaining capacity limits of equipments; obtaining a standard amount of wafers manufactured by equipments from the capacity scheme system; calculating the deficiencies of equipments by estimating the standard amount of wafers manufactured by equipments; dispatching lots of wafers by the two-way dispatching method of manufacturing IC which estimating the priority of lots of wafers, the capacity limits of equipments and the deficiencies of equipments; printing a dispatching list of the result dispatching by the two-way dispatching method of manufacturing IC.
The two-way dispatching method of manufacturing IC of the present invention employs push and pull two-way, and is concerned with not only short-term arrangement in the IC factory, but also the balance of production line, so as to increase the utility of equipments.